Systems and methods for maintaining sulfur concentration in a syngas to reduce metal dusting in downstream components

ABSTRACT

Systems and methods for maintaining a sulfur concentration in a syngas are provided. The method can include combining sulfur and a carbonaceous material to produce a sulfur containing carbonaceous feed. The method can also include gasifying at least a portion of the sulfur containing carbonaceous feed to produce a syngas and detecting a sulfur concentration in the syngas. The method can further include adjusting an amount of the sulfur combined with the carbonaceous material based on the detected sulfur concentration.

BACKGROUND

1. Field

Embodiments described generally relate to systems and methods forproducing synthesis gas. More particularly, such embodiments relate tosystems and methods for maintaining sulfur concentration in a syngas toreduce metal dusting in downstream components.

2. Description of the Related Art

A gasifier produces synthesis gas or “syngas” and the syngas can befurther processed downstream. Downstream components made of metal, suchas exchanger tubes, can suffer from metal dusting, also known ascarburization, due to interaction with the syngas, particularly at hightemperatures. The term “metal dusting” refers to severe and aggressivecorrosion that can disintegrate metal into dust or powder.

Various approaches have been used to reduce the causes and/or effects ofmetal dusting. One approach has been selecting alloys that are resistantto metal dusting for use in the downstream components. Another approachhas been to apply a coating to the downstream components with a coatingmaterial that minimizes metal dusting. These two approaches, however,require expensive modifications and/or replacement of components used inexisting gasifier systems.

Sulfur is a known inhibitor of metal dusting. The sulfur can be absorbedonto the surface of the metal and block gas to metal transfer of carbon.Typical feeds to a gasifier, e.g., coal or carbonaceous feedstock,contain sulfur. The sulfur levels in these gasifier feeds, however, canbe below the minimum level of sulfur needed to reduce or prevent metaldusting.

There is a need, therefore, for systems and methods for producing asyngas with a sulfur concentration sufficient to reduce metal dusting incomponents downstream of the gasifier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic of an illustrative gasification system forproducing a syngas having a sulfur concentration sufficient to reducemetal dusting in components downstream of one or more gasifiers,according to one or more embodiments described.

FIG. 2 depicts a schematic of another illustrative gasification systemfor producing a syngas having a sulfur concentration sufficient toreduce metal dusting in components downstream of one or more gasifiers,according to one or more embodiments described.

DETAILED DESCRIPTION

Systems and methods for maintaining a sulfur concentration in a syngasare provided. The method can include combining sulfur and a carbonaceousmaterial to produce a sulfur containing carbonaceous feed. The methodcan also include gasifying at least a portion of the sulfur containingcarbonaceous feed to produce a syngas and detecting a sulfurconcentration in the syngas. The method can also include adjusting anamount of the sulfur combined with the carbonaceous material based onthe detected sulfur concentration.

FIG. 1 depicts a schematic of an illustrative gasification system 100for producing a syngas via line 151 having a sulfur concentrationsufficient to reduce metal dusting in components downstream of agasifier 150, according to one or more embodiments. The gasificationsystem 100 can include one or more lock hoppers or storage bins 110, 130for feeding one or more gasifier feed systems 140, wherein the gasifierfeeds can be stored or treated prior to entering the one or moregasifiers 150 to produce syngas. Elemental sulfur can be stored in oneor more “first” lock hoppers or storage bins 110, which can be any unitadapted to retain and/or dispense sulfur. One or more feeders 120 candispense the sulfur from the first lock hopper 110 via line 122 to oneor more “second” lock hoppers or storage bins 130 for storing thefeedstock for gasification to combine the sulfur with the feedstock.

Although not shown, the feeder 120 can dispense sulfur from the firstlock hopper 110 onto and/or into a conveyance device that, in turn, cantransport or convey sulfur to the second lock hopper 130. For example,the conveyance device can be a conveyor belt, a slide, a chute, anincline, or a combination thereof. The conveyance device can furthercontrol the rate of sulfur dispensed into the second lock hopper 130.For example, if the conveyance device is a conveyor belt, the speed ofthe belt can be adjusted to dispense sulfur either slowly or rapidly,depending, for example, on sulfur amounts measured further along in thesystem.

The second lock hopper 130 can receive, store, and/or mix the feedstockand the sulfur so that a sulfur containing carbonaceous material can beobtained therein. The second hopper 130 can convey or dispense thesulfur containing carbonaceous material via line 131 to the gasifierfeed system 140. Preferably, the sulfur containing carbonaceous materialcan be conveyed from the second lock hopper 130 to the gasifier feedsystem 140 via line 131 at a rate of at least 50 kilograms per hour(kg/hr), and more preferably at a rate between a low of about 75 kg/hr,about 100 kg/hr, or about 125 kg/hr and a high of about 450 kg/hr, about500 kg/hr, or about 550 kg/hr. The second lock hopper 130 can include afeeder (not shown), such as a high-pressure rotary feeder, that cancooperate with an added fluid stream (not shown) to convey the sulfurcontaining carbonaceous material via line 131 to the gasifier feedsystem 140.

The term “feedstock” as used herein refers to one or more carbonaceousmaterials, whether solid, gas, liquid, or any combination thereof. Thefeedstock can include one or more carbonaceous materials (i.e.,carbon-containing materials) including, but not limited to, biomass(i.e., plant and/or animal matter or plant and/or animal derivedmatter), coal (i.e., high-sodium and low-sodium lignite, lignite,subbituminous, and/or anthracite), oil shale, coke, tar, asphaltenes,low ash or no ash polymers, hydrocarbon-based polymeric materials,biomass derived material, by-product derived from manufacturingoperations, or any combination thereof. The hydrocarbon-based polymericmaterials can include, but are not limited to, thermoplastics,elastomers, rubbers, including polypropylenes, polyethylenes,polystyrenes, including other polyolefins, homo polymers, copolymers,block copolymers, PET (polyethylene terephthalate), poly blends,poly-hydrocarbons containing oxygen, heavy hydrocarbon sludge andbottoms products from petroleum refineries and petrochemical plants suchas hydrocarbon waxes, blends thereof, derivatives thereof, or anycombination thereof.

The feedstock can include a mixture or combination of two or more lowash or no ash polymers, biomass derived materials, or by-productsderived from manufacturing operations. For example, the feedstock caninclude one or more carbonaceous materials combined with one or morediscarded consumer products, such as carpet and/or plastic automotiveparts/components, e.g., bumpers or dashboards. As necessary, suchdiscarded consumer products can be reduced in size, for example groundup, prior to or during processing through the gasification system 100.The feedstock can also include one or more recycled plastics such aspolypropylene, polyethylene, polystyrene, derivatives thereof, blendsthereof, or any combination thereof. Accordingly, the gasificationsystem 100 can be useful for accommodating mandates for proper disposalof previously manufactured materials.

The feedstock can be dried and then pulverized by one or more millingunits (not shown) prior to being introduced to the second lock hopper130 via line 101. For example, the feedstock via line 101 can be driedfrom a high of about 35% moisture to a low of about 18% moisture. Afluid bed drier (not shown) can be used to dry the feedstock via line101, for example.

The feedstock via line 101 can have an average particle size rangingfrom a low of about 1 micron, about 10 microns, about 50 microns, about100 microns, about 150 microns, or about 200 microns to a high of about1,350 microns, about 1,400 microns, about 1,450 microns, or about 1,500microns. For example, the average particle size of the feedstock vialine 101 can range from about 75 microns to about 1,475 microns, fromabout 125 microns to about 1,425 microns, or about 175 microns to about1,375 microns. In another example, the feedstock via line 101 can beground to have an average particle size of about 300 microns or less.

The gasifier feed system 140 can receive the sulfur containingcarbonaceous material via line 131 to produce a first feed or “gasifier”feed via line 141. The gasifier feed system 140 can provide a controlledflow of the sulfur containing carbonaceous material or carbonaceous feedinto the gasifier 150 via line 141, while simultaneously accommodatingfor pressure changes within the gasifier 150. The gasifier feed system140 can include one or more lock vessels or storage bins, one or moredispensing vessels, and/or one or more feeders connected by one or morevalves.

Alternatively, sulfur can be added via line 123 directly to the gasifierfeed system 140, bypassing the second lock hopper 130. In anotherexample, the sulfur via line 124 can be added to the gasifier feed inline 141 instead of adding sulfur via line 121 to the second lock hopper130 or the gasifier feed system 140. In yet another example, the sulfurvia line 124 can be added to the gasifier feed of line 141 inconjunction with adding sulfur via line 121 to the second lock hopper130 and/or adding sulfur via line 123 to the gasifier feed system 140.Although not shown, sulfur added via line 124 can be pressurized to apressure of the gasifier feed in line 141 and/or the pressure of thegasifier 150 prior to introduction to the gasifier feed in line 141and/or the gasifier 150.

The gasifier feed via line 141 can have an average particle size of froma low of about 1 micron, about 10 microns, about 50 microns, about 100microns, or about 150 microns to a high of about 400 microns, about 450microns, or about 500 microns. For example, the gasifier feed via line141 can have an average particle size ranging from about 75 microns toabout 475 microns, about 125 microns to about 425 microns, or from about250 microns to about 350 microns.

The gasifier feed via line 141 can be introduced to the one or moregasifiers 150 to produce a raw syngas stream via line 151. The gasifier150 can gasify at least a portion of the gasifier feed introduced vialine 141 to produce the raw syngas stream via line 151. The gasifierfeed via line 141 can be a dry feed or can be conveyed to the gasifier150 as a slurry or suspension. The gasifier feed or sulfur containingcarbonaceous material in line 141 can have a sulfur concentrationsufficient to produce a syngas via line 151 capable of reducing orpreventing metal dusting in the downstream process equipment. Forexample, the sulfur concentration in the gasifier fed via line 141 canbe an amount sufficient to produce a raw syngas via line 151 having asulfur concentration of at least 0.1 percent by volume (vol %), at least0.2 vol %, or at least 0.3 vol %. The sulfur concentration of the rawsyngas in line 151 can vary depending, at least in part, on the amountof sulfur added to the second lock hopper 130, the gasifier feed system140, and/or the gasifier feed via line 141. For example, the sulfurconcentration of the raw syngas in line 151 can be about 0.01 vol % ormore, 0.05 vol % or more, about 0.1 vol % or more, about 0.15 vol % ormore, about 0.2 vol % or more, about 0.25 vol % or more, about 0.3 vol %or more, about 0.35 vol % or more, about 0.4 vol % or more, about 0.45vol % or more, about 0.5 vol % or more, about 0.6 vol % or more, about0.7 vol % or more, about 0.8 vol % or more, about 0.9 vol % or more, orabout 1 vol % or more. In another example, the sulfur concentration ofthe raw syngas stream 151 can range from about 0.1 vol % to about 0.4vol %. The sulfur can be present in the form of hydrogen sulfide,carbonyl sulfide, and other sulfur containing compounds.

The raw syngas in line 151 can also contain about 60 vol % or morecarbon monoxide and hydrogen with additional components includingprimarily carbon dioxide and methane. For example, the raw syngas inline 151 can contain about 90 vol % or more carbon monoxide andhydrogen, about 95 vol % or more carbon monoxide and hydrogen, about 97vol % or more carbon monoxide and hydrogen, or about 99 vol % or morecarbon monoxide and hydrogen. In one example, the carbon monoxidecontent of the raw syngas in line 151 can range from a low of about 10vol %, about 20 vol %, or about 30 vol % to a high of about 50 vol %,about 70 vol % or about 85 vol %. In another example, the carbonmonoxide content of the raw syngas in line 151 can range from a low ofabout 15 vol %, about 25 vol %, or about 35 vol % to a high of about 65vol %, about 75 vol % or about 85 vol %. The hydrogen content of the rawsyngas in line 151 can range from a low of about 1 vol %, about 5 vol %,or about 10 vol % to a high of about 30 vol %, about 40 vol % or about50 vol %. For example, the hydrogen content of the raw syngas in line151 can range from about 20 vol % to about 30 vol %.

The raw syngas in line 151 can contain less than about 25 vol % or less,about 20 vol % or less, about 15 vol % or less, about 10 vol % or less,or about 5 vol % or less of combined nitrogen, methane, carbon dioxide,water, hydrogen sulfide, and hydrogen chloride. The carbon dioxidecontent of the raw syngas in line 151 can be about 25 vol % or less,about 20 vol % or less, about 15 vol % or less, about 10 vol % or less,about 5 vol % or less, about 3 vol % or less, about 2 vol % or less, orabout 1 vol % or less. The methane content of the raw syngas in line 151can be about 15 vol % or less, about 10 vol % or less, about 5 vol % orless, about 3 vol % or less, about 2 vol % or less, or about 1 vol % orless. The water content of the raw syngas in line 151 can be about 40vol % or less, about 30 vol % or less, about 25 vol % or less, about 20vol % or less, about 15 vol % or less, about 10 vol % or less, about 5vol % or less, about 3 vol % or less, about 2 vol % or less, or about 1vol % or less. The raw syngas in line 151 can be nitrogen-free oressentially nitrogen-free, e.g., containing about 0.5 vol % or lessnitrogen.

The raw syngas in line 151 can have a heating value, corrected for heatlosses and dilution effects, of about 1,863 kJ/m³ (50 Btu/scf) to about2,794 kJ/m³ (75 Btu/scf); about 1,863 kJ/m³ to about 3,726 kJ/m³ (100Btu/scf); about 1,863 kJ/m³ to about 4,098 kJ/m³ (110 Btu/scf); about1,863 kJ/m³ to about 5,516 kJ/m³ (140 Btu/scf); about 1,863 kJ/m³ toabout 6,707 kJ/³ (180 Btu/scf); about 1,863 kJ/m³ to about 7,452 kJ/m³(200 Btu/scf); about 1,863 kJ/m³ to about 9,315 kJ/m³ (250 Btu/scf);about 1,863 kJ/m³ to about 10,246 kJ/m³ (275 Btu/sef), 1,863 kJ/m³ toabout 11,178 kJ/m³ (300 Btu/scf), or about 1,863 kJ/m³ to about 14,904kJ/m³ (400 Btu/scf).

One or more analyzers 160 can be used to control the rate and amount ofsulfur to the gasifier 150. The analyzer 160 can be used to detect ormeasure the amount of sulfur and/or sulfur compounds, i.e., the sulfurcontent or concentration, in the raw syngas and can communicate with thefeeder 120 and/or the first lock hopper 110 via a communication link 161to control the rate and/or amount of sulfur added to the second lockhopper 130, the gasifier feed system 140, the gasifier feed in line 141,and/or directly injected into the gasifier 150 (not shown). Thecommunication link 161 can be wired, wireless, or a combination thereof.In another example, the analyzer 160 can alert personnel of the sulfurconcentration in the raw syngas in line 151 and the rate and/or amountof sulfur added to the second lock hopper 130, the gasifier feed system140, the gasifier feed in line 141, and/or directly injected into thegasifier 150 (not shown) can be manually adjusted or controlled.

The analyzer 160 can be located downstream of the gasifier 150, e.g.,past one or more coolers (not shown) and/or one or more particulateremoval units (not shown) to allow for cooling of the syngas and/orremoval of at least portion of the entrained solids prior to detectingor measuring the sulfur concentration in the syngas, respectively. Forexample, the analyzer 160 can measure the sulfur concentration of thesyngas once it has been cooled to a temperature of about 600° C. orless, about 500° C. or less, about 450° C. or less, about 400° C. orless, about 350° C. or less, about 300° C. or less, about 250° C. orless, or about 200° C. or less. In another example, the analyzer 160 canmeasure the sulfur concentration of the syngas once it has been cooledto a temperature of less than 350° C. In yet another example, theanalyzer 160 can measure the sulfur concentration of the syngas once thelevel of particulates in the syngas has been reduced to about 10 ppmw orless, about 5 ppmw or less, about 1 ppmw or less, about 0.3 ppmw orless, about 0.2 ppmw or less, or about 0.1 ppmw or less.

The analyzer 160 can be any analyzer or technique capable of estimating,detecting, or measuring an amount or concentration of sulfur or sulfurcompounds in the syngas. For example, the analyzer 160 can use gaschromatography, vapor-phase chromatography, and/or gas-liquid partitionchromatography to detect, measure, or otherwise estimate the sulfurconcentration in the raw syngas stream 151 coming out of the gasifier150. The analyzer 160 can use a flow-through narrow tube or column,through which different chemical constituents of a sample pass in a gasstream or carrier gas at different rates depending on their variouschemical and physical properties and their interaction with a specificcolumn filling, referred to as a stationary phase. The passing of thecarrier gas can be referred to as the moving or mobile phase. The movingphase can utilize a carrier gas including, but not limited to, an inertgas such as helium or an unreactive gas such as nitrogen. The analyzer160 can also be or include a spectrometer, laser spectrometer,aerograph, gas separator, or any combinations of the foregoinganalytical equipment or techniques.

Detectors that can be used in the analyzer 160 can include, but are notlimited to, flame ionization detectors (FID), thermal conductivitydetectors (TCD), discharge ionization detectors (DID), electron capturedetectors (ECD), flame photometric detectors (FPD), flame ionizationdetectors (FID), Hall electrolytic conductivity detectors (HECD), heliumionization detectors (HID), nitrogen phosphorus detectors (NPD),infrared detectors (IRD), mass selective detectors (MSD),photo-ionization detectors (PID), pulsed discharge ionization detectors(PDD), thermal energy (conductivity) analyzer/detectors (TEA/TCD), massspectrometers, infrared spectrophotometers, nuclear magnetic resonance(NMR) spectrometers, or a combination thereof.

In operation, the feeder 120 can be automatically and/or manuallyadjusted according to the signal and/or data conveyed in thecommunication link 161. The feeder 120 can be a metered feeder or arotofeed dispenser, and can be driven by a variable speed electric motor(not shown) to adjust the feed rate and amounts of the sulfur. When theanalyzer 160 detects an insufficient amount of sulfur and/or sulfurcompounds in the raw syngas in line 151, i.e., the sulfur concentrationis below a predetermined value or a desired first or “lower” threshold,the feeder 120 can be adjusted to increase the rate at which the sulfurvia line 122 is dispensed or conveyed to the second lock hopper 130, thegasifier feed system 140, and/or the gasifier feed in line 141. Aninsufficient amount of sulfur in the raw syngas in line 151 refers to asulfur concentration of less than about 0.1 vol %, based on the totalvolume of the raw syngas in line 151.

When the analyzer 160 detects an excess amount of sulfur and/or sulfurcompounds in the raw syngas in line 151, i.e., the sulfur concentrationor concentration is above a desired second or “upper” threshold, thefeeder 120 can be automatically and/or manually adjusted to decrease therate at which the sulfur via line 122 is dispensed or conveyed to thegasifier feed system 140, the rate at which the sulfur via line 123 isadded to the gasifier feed system 140, and/or the rate at which thesulfur via line 124 is introduced to the gasifier 150 via line 141. Forexample, when the sulfur concentration in the raw syngas in line 151increases above about 0.4 vol %, about 0.5 vol %, about 0.6 vol %, about0.7 vol %, about 0.8 vol %, about 0.9 vol %, or about 1 vol %, theamount of sulfur introduced to the second lock hopper 130, the gasifierfeed system 140, and/or the gasifier feed in line 141 can be reducedand/or stopped. In this way the sulfur concentration in the raw syngasstream 151 can be automatically or manually controlled to maintain thesulfur concentration within a predetermined or desired range to reduceor prevent metal dusting in components downstream of the gasifier 150.

Considering the gasifier 150 in more detail, the gasifier 150 can be orinclude one or more circulating solid or transport gasifiers, one ormore fixed bed gasifiers, one or more fluidized bed gasifiers, one ormore entrained flow gasifiers, or a combination thereof. For example,circulating solid gasifiers can operate by introducing one or moreoxidants to a feed stream, e.g., the gasifier feed via line 141, and/orto one or more mixing zones (not shown) to provide a gas mixture. Inanother example, the oxidant can be added directly to the gasifier. Thetype and amount of oxidant introduced to circulating solid gasifiers caninfluence the composition and physical properties of the syngas via line151 and hence, the downstream products made therefrom. The one or moreoxidants can be introduced into the one or more mixing zones to producea gas mixture, and, for example, can be introduced at a rate suitable tocontrol the temperature of the mixing zone. The gas mixture can moveupward through the mixing zone into a riser (not shown) where residencetime can allow char gasification, methane/steam reforming, tar cracking,and/or water-gas shift reactions to occur. The temperature in the mixingzone can start at from about 500° C. to about 650° C. and increase toabout 900° C., for example if a coke breeze or an equivalent is fedtherein. In one example, the riser can operate at a higher temperaturethan the mixing zone. The gas mixture can exit the riser and enter oneor more disengagers or cyclones (not shown) where large particulates canbe separated from the gas and recycled back to the mixing zone.

The residence time within circulating solid gasifiers can be from about2 seconds or more to about 10 seconds or more, where the temperature canbe sufficient for water-gas shift reactions to reach equilibrium (i.e.,temperatures ranging from a low of about 250° C. to a high of about1,000° C.). The operating temperature of circulating solid gasifiers canbe controlled, at least in part, by the recirculation rate and residencetime of the solids within the riser, by reducing the temperature of theash prior to recycle to the mixing zone, by the addition of steam to themixing zone, and/or by the addition of oxidant to the mixing zone.Recirculated solids can serve to rapidly heat the incoming gasifier feedvia line 141, which can minimize tar formation. The mixing zone can beoperated at pressures of from about 100 kilopascals (kPa) to about 4500kPa to increase thermal output per unit reactor cross-sectional area andenhance energy output in any subsequent power cycle.

Since the outlet temperature of a circulating solid gasifier can beproportionately less than comparable gasifiers (e.g., slag type), theamount of thermal heat versus chemical heat in the syngas can becomparably less in the circulating solid gasifier. Because of thereduced operating temperature within the gasifier (i.e., less than1,600° C.), less energy can be consumed to control and optimize theH₂:CO ratio, thus the production of hydrogen can be increased without acommensurate increase in steam demand within the gasifier. Suitablecirculating solid gasifiers can be as discussed and described in U.S.Pat. No. 7,722,690 and U.S. Patent Application Nos. 02008/0155899,2009/0151250, and 2009/0188165.

In another example, fixed bed or moving bed gasifiers can operate byintroducing the gasifier feed via line 141 into an upper or top part ofa reactor (not shown). Oxygen and/or steam can be introduced to fixedbed gasifiers at a lower or bottom part of the reactor. The feed canmove down through the reactor by gravity and can be gasified. Ashremaining from the gasification can drop out of the bottom part of thereactor. Fixed bed gasifiers can be operated at relatively low outlettemperature (425° C. to 700° C.) and can require a lesser amount ofoxygen compared to fluidized bed gasifiers and entrained flow gasifiers,but can have a high demand for steam and produce significant amounts oftar. Fixed bed gasifiers can have a limited ability to handle fines andcan have special requirements for handling caking coal. The productsyngas from fixed bed gasifiers can contain unconverted methane and/orby-product tars and oils. Suitable fixed bed gasifiers can be asdiscussed and described in U.S. Pat. Nos. 4,290,780; 4,417,528; and5,069,685 and U.S. Patent Application No. 2008/0086945.

In yet another example, fluidized bed gasifiers can operate by mixingsolid particles from the gasifier feed via line 141 with older,partially gasified and/or fully gasified particles in a reactor (notshown). The solid particles can be fluidized with a gas and then the gasand remaining solid particles can be separated. Gas in the reactor caninclude oxygen, steam, recycled syngas, or a combination thereof. Theflow of the gas into the reactor can be sufficient to float the solidparticles without entraining them out of the reactor. Fluidized bedgasifiers can operate at moderate outlet temperatures and thetemperature can be uniform throughout the bed. For example, fluidizedbed gasifiers can operate at a temperature ranging from a low of about700° C., about 750° C., about 800° C., or about 850° C. to a high ofabout 1,000° C., about 1,050° C., about 1,100° C., or about 1,150° C.Fluidized bed gasifier can require a greater amount of oxygen thancomparable fixed bed gasifiers but less than comparable entrained flowgasifiers. Likewise, fluidized bed gasifier can require less steam thancomparable fixed bed gasifiers but more than comparable entrained flowgasifiers. The syngas from fluidized bed gasifiers can be of higherpurity than the syngas from comparable entrained flow gasifiers and thecarbon conversion can be lower than comparable entrained flow gasifiers.Purity can be measured by the amount of H₂+CO in the syngas. Forexample, the purity of the syngas in a fluidized bed gasifier can rangefrom 25% to 90% H₂+CO. The carbon conversion in a fluidized bed gasifiercan range, for example, from a low of about 92%, about 93%, or about 94%to a high of about 97%, about 98%, or about 99%. Suitable fluidized bedgasifiers can be as discussed and described in U.S. Pat. Nos. 4,696,678;6,972,114; and 7,503,945 and U.S. Patent Application No. 2008/0250714.

In still another example, entrained flow gasifiers can operate byinjecting the gasifier feed via line 141 in co-concurrent flow with anoxidant into a reactor bed (not shown). The gasifier feed rapidly heatsup and reacts with the oxidant. The oxidant can be oxygen, steam,recycled syngas, or a combination thereof. Entrained flow gasifiers canrequire a large amount of oxidant and can require high oxygen purity.For example, entrained flow gasifiers can require from about 0.2 normalcubic meters (“Nm³”) O₂ to about 0.5 Nm O₂ per Nm³ (H₂+CO). In addition,an oxidant introduced to an entrained flow gasifier can have a purity ofabout 99.5 vol % or more. Entrained flow gasifiers can operate at hightemperatures, and often require a high temperature to achieve highcarbon conversion. For example, entrained flow gasifiers can operate ata temperature ranging from a low of about 1,150° C., about 1,200° C.,about 1,250° C., or about 1,300° C. to a high of about 1,550° C., about1,600° C., about 1,650° C., or about 1,700° C. Entrained flow gasifierscan also require higher energy input than fixed bed gasifiers in theform of higher specific steam and/or oxygen consumption. Entrained flowgasifiers can obtain a high purity syngas and can gasify a large rangeof materials. For example, the syngas from an entrained flow gasifiercan have less than about 0.5% N₂, no tars, and parts per million ofmethane. Entrained flow gasifiers can have short residence times, i.e.,from a low of about 0.1 seconds, about 0.2 seconds, or about 0.3 secondsto a high of about 1 second, about 2 seconds, or about 3 seconds.Suitable entrained flow gasifiers can be as discussed and described inU.S. Pat. Nos. 4,158,552; 4,531,949; and 5,620,487 and U.S. PatentApplication No. 2010/0088959.

FIG. 2 depicts a schematic of another illustrative gasification system200 for producing a syngas via line 251 having a sulfur concentrationsufficient to reduce metal dusting in components downstream of one ormore gasifiers (one is shown 250), according to one or more embodiments.Similar to the embodiment discussed and described above with referenceto FIG. 1, sulfur can be stored in one or more first lock hoppers orstorage bins 110. The first lock hopper 110 can be in communication witha first or “sulfur” feeder 220 either directly or via line 111. Thefirst feeder 220 can dispense the sulfur from the first lock hopper 110via lines 221 and 222 to the one or more second lock hoppers 130. Thefirst feeder 220 can control the amount and/or rate of sulfur dispensedvia line 221 into the second lock hopper 130. For example, the firstfeeder 220 can be a metered feeder or a rotofeed dispenser, and can bedriven by a variable speed electric motor (not shown). The sulfur can bepulverized or ground prior to being fed to the first lock hopper 110and/or the first feeder 220, and can have an average particle size afterbeing pulverized to the dimensions discussed and described above withreference to the first lock hopper 110 and the feeder 120 in FIG. 1.

The second lock hopper 130 can receive, store, and/or mix the feedstockvia line 101 and the sulfur via line 222 and can convey or dispense asulfur containing carbonaceous material via line 239 to the gasifierfeed system 240. Alternatively, sulfur can be added directly to thegasifier feed system 240, bypassing the second lock hopper 130. Forexample, sulfur via line 223 can be added to one or more storage bins242 of the gasifier feed system 240 in lieu of adding sulfur via lines221 and 222 to the second lock hopper 130.

The second lock hopper 130 can operate via line 231 in conjunction witha second feeder 234, such as a high pressure rotary feeder thatcooperates with an added fluid stream (not shown) to convey thecarbonaceous material via line 239 to the gasifier feed system 240.Illustrative fluids can include, but are not limited to, air, nitrogen,carbon dioxide, or any combination thereof. Preferably, the carbonaceousmaterial can be conveyed from the second lock hopper 130 to the gasifierfeed system 240 at a rate of at least 10,000 kg/hr, and more preferablyat a rate between about 20,000 kg/hr and a high of about 30,000 kg/hr.

The gasifier feed system 240 can receive the sulfur containingcarbonaceous material via line 239 and/or from another process or source(not shown) and produce a gasifier feed via line 241. The gasifier feedsystem 240 can include the storage bin 242, one or more first or “lock”vessels 244, one or more second or “dispensing” vessels 246, and one ormore second feeders 248. The storage bin 242 can be joined to and/or influid communication with the lock vessel 244 by one or more firstcontrol valves 243, and the storage bin 244 can be joined to and/or influid communication with the dispensing vessel 246 by one or more secondcontrol valves 245.

The carbonaceous material from the second lock hopper 130 via line 239and any additional sulfur via line 223 can be introduced to the storagebin 242. Nitrogen via a low pressure nitrogen source 202 can be added tothe storage bin 242 to maintain atmospheric pressure within the storagebin 242. Sulfur added to the storage bin 242 can mix with thecarbonaceous material in the storage bin 242 to provide a sulfurcontaining carbonaceous material in the lock vessel 244 and/or thedispensing vessel 246.

The carbonaceous material via line 239 can be with or without sulfuradded and can be dried and/or pulverized. For example, the carbonaceousmaterial via line 101 can be dried and pulverized by one or more millingunits (not shown) prior to being fed to the second lock hopper 130. Forexample, the feedstock via line 101 can be dried to about 22% to about15% moisture. In another example, the feedstock via line 101 can bedried to about 18% moisture. In one or more embodiments, a fluid beddrier (not shown) can be used to dry the feedstock via line 101. Thecarbonaceous material via line 239 can be dried and pulverized by one ormore milling units (not shown) prior to being fed to the storage bin242. The milling unit can include, for example, one or more bowl millsor one or more rod mills (not shown).

Sulfur containing carbonaceous material from the storage bin 242 can befed into the lock vessel 244 at a controlled rate or intermittently. Thelock vessel 244 can be isolated from the storage bin 242 by closing thefirst control valve 243. The lock vessel 244 can be pressurized to afirst or “full system” pressure with nitrogen via a first high pressurenitrogen source 203.

The first pressure in the lock vessel 244 can range from a low of about2,400 kPa, about 2,600 kPa, about 2,800 kPa, or about 3,000 kPa to ahigh of about 4,000 kPa, about 4,200 kPa, about 4,400 kPa, or about4,600 kPa. For example, the first pressure in the lock vessel 244 canrange from about 2,500 kPa to about 4,500 kPa, from about 2,700 kPa toabout 4,300 kPa, or from about 2,900 kPa to about 4,100 kPa. In anotherexample, the first pressure can be about 3,500 kPa. The dispensingvessel 246 can remain at the first pressure.

Once the sulfur containing carbonaceous material in the lock vessel 244has reached the first pressure, i.e., the pressure of the dispensingvessel 246, the second control valve 245 between the lock vessel 244 andthe dispensing vessel 246 can be opened. The sulfur containingcarbonaceous material can then feed into the dispensing vessel 246 bygravity until the full inventory of the lock vessel 244 is dischargedinto the dispensing vessel 246. The lock vessel 244 can then be isolatedfrom the dispensing vessel 246 and depressurized in preparation forreceiving another charge of sulfur containing carbonaceous material fromthe storage bin 242.

The dispensing vessel 246 can operate continuously at the firstpressure. Pressure in the dispensing vessel 246 can be maintained withnitrogen via a second high pressure nitrogen source 204. The sulfurcontaining carbonaceous material can be transported from the bottom ofthe dispensing vessel 246 into one or more gasifiers 250 through thesecond feeder 248.

The second feeder 248 can be a non-mechanical feed control device withno moving parts and can combine continuous ash depressurization systemswith traditional designs for flow rate control. The driving force forthe flow of the sulfur containing carbonaceous material in the feeder248 can be differential pressure therein. Nitrogen gas via a third highpressure nitrogen source 205 and transport fluid, e.g., air and/orrecycled syngas, via a transport fluid source 206 can meter the flow ofthe sulfur containing carbonaceous material through and out of thefeeder 248 into the gasifier 250.

The gasifier feed via line 241 can be introduced to the gasifier 250 toproduce a raw syngas stream 251. The gasifier feed in line 241 can be adry feed or can be conveyed to the gasifier 250 as a slurry orsuspension. The gasifier 250 can be, but is not limited to, one or morecirculating solid gasifiers, one or more fixed bed gasifiers, one ormore fluidized bed gasifiers, one or more entrained flow gasifiers, or acombination thereof.

The gasifier 250 can include a single reactor train or two or morereactor trains arranged in series or parallel. Each reactor train caninclude one or more mixing zones 252, one or more risers 253, and one ormore disengagers 254. Each reactor train can be configured independentfrom the others or configured where any of the one or more mixing zones252, risers 253, or disengagers 254 can be shared. For simplicity andease of description, embodiments of the gasifier 250 will be furtherdescribed in the context of a single reactor train.

The gasifier feed via line 241 and one or more oxidants or process airvia line 214 can be combined in the mixing zone 252 to provide a gasmixture or suspension. The gasifier feed via line 241 and oxidant vialine 214 can be injected separately, as shown, to the mixing zone 252 ormixed prior to injection into the mixing zone (not shown). For example,the gasifier feed via line 241 and oxidant via line 214 can be injectedsequentially into the gasifier 250. In another example, the gasifierfeed via line 241 and oxidant via line 214 can be injectedsimultaneously into the gasifier 250.

The type and amount of oxidant introduced via line 214 to gasifier 250can influence the composition and physical properties of the syngas vialine 251 and hence, the downstream products made therefrom. The one ormore oxidants can include, but are not limited to, air, oxygen,essentially oxygen, oxygen-enriched air, mixtures of oxygen and air,mixtures of oxygen and inert gas such as nitrogen and argon, and thelike. The oxidant can contain about 65 vol % oxygen or more, about 70vol % oxygen or more, about 75 vol % oxygen or more, about 80 vol %oxygen or more, about 85 vol % oxygen or more, about 90 vol % oxygen ormore, about 95 vol % oxygen or more, or about 99 vol % oxygen or more.As used herein, the term “essentially oxygen” refers to an oxygen streamcontaining 51 vol % oxygen or more. As used herein, the term“oxygen-enriched air” refers to air containing 21 vol % oxygen or more.Oxygen-enriched air can be obtained, for example, from cryogenicdistillation of air, pressure swing adsorption, membrane separation, orany combination thereof. At least one of the oxidants can be pure oxygensupplied from one or more air separation units (not shown). The one ormore oxidants can be nitrogen-free or essentially nitrogen-free. By“essentially nitrogen-free,” it is meant that the one or more oxidantscontain about 5 vol % nitrogen or less, about 4 vol % nitrogen or less,about 3 vol % nitrogen or less, about 2 vol % nitrogen or less, or about1 vol % nitrogen or less.

The gas mixture can move upward through the mixing zone 252 into theriser 253 where additional residence time allows the char gasification,methane/steam reforming, tar cracking, and/or water-gas shift reactionsto occur. The riser 253 can operate at a higher temperature than themixing zone 252, and can have a smaller diameter than the mixing zone252. Suitable temperatures in the riser 253 can range from a low ofabout 700° C., about 715° C., about 730° C., or about 750° C. to a highof about 950° C., about 1,000° C., about 1,050° C., or about 1,100° C.For example, suitable temperatures in the riser 253 can range from about710° C. to about 1,075° C., about 720° C. to about 1,025° C., or about740° C. to about 975° C. The superficial gas velocity in the riser 253can range from a low of about 3 meters per second (m/s), about 6 m/s, orabout 9 m/s to a high of about 21 m/s, about 24 m/s, or about 27 m/s.For example, the superficial gas velocity in the riser 253 can rangefrom about 5 m/s to about 25 m/s, from about 10 m/s to about 18 m/s, orfrom about 9 m/s to about 12 m/s.

The gas mixture can exit the riser 253 and enter the disengagers 254where larger particulates can be separated from the gas and recycledback to the mixing zone 252 via one or more conduits, including, but notlimited to, a standpipe 259, and/or j-leg 258. The j-leg 258 can includea non-mechanical “j-valve” to increase the effective solids residencetime, increase the carbon conversion, and minimize aeration requirementsfor recycling solids to the mixing zone 252. In one or more embodiments,the disengagers 254 can be cyclones. One or more particulate transferdevices 257, such as one or more loop seals or seal legs, can be locateddownstream of the disengagers 254 to collect separated particulatefines. Although not shown, a second stage solids separator or cyclonecan be disposed or located on the standpipe 259 to separate out amajority of fines solids coming from a top of the disengagers 254. Anyentrained or residual particulates in the raw syngas stream 251 can beremoved using the one or more particulate removal systems or particulatecontrol devices 290. Recycle gas via line 208, e.g., from a compressor(not shown), can be added to the j-leg 258, the particulate transferdevice 257, the standpipe 259, or any combination thereof, for aerationto aid in solids circulation.

The one or more oxidants via line 214 can be introduced at the bottom ofthe mixing zone 252 to increase the temperature within the mixing zone252 and riser 253 and combust any carbon contained within therecirculated particulates in the form an ash (“char”). For example, theone or more oxidants can be introduced into the mixing zone 252 at arate suitable to control the temperature of the mixing zone 252. The oneor more oxidants can include excess air. For example, the one or moreoxidants can be sub-stoichiometric air wherein the molar ratio of oxygento carbon can be maintained at a sub-stoichiometric concentration tofavor the formation of carbon monoxide over carbon dioxide in the mixingzone 252. In another example, the oxygen supplied via the oxidant to themixing zone 252 can be less than five percent of the stoichiometricamount of oxygen required for complete combustion of all the carbonsupplied to the mixing zone 252. Additional oxygen and steam in the aircan be consumed by the char in the recirculating solids, therebystabilizing reactor temperature during operation and during periods offeed interruption.

The residence time and temperature in the gasifier 250 can be sufficientfor water-gas shift reaction to reach equilibrium. For example, theresidence time of the gasifier feed via line 241 in the mixing zone 252can be greater than about 2 seconds, greater than about 5 seconds, orgreater than about 10 seconds. The operating temperature of the gasifier250 can range from a low of about 600° C., about 650° C., or about 700°C. to a high of. about 900° C., about 1,000° C., or about 1,100° C. Forexample, the operating temperature of the gasifier 250 can range fromabout 625° C. to about 1,050° C., from about 675° C. to about 1,025° C.,or from about 700° C. to about 975° C.

The gasifier 250 can be operated in a temperature range sufficient tonot melt the ash, such as from about 565° C. to about 1040° C. or fromabout 840° C. to about 930° C. Heat can be supplied by burning thecarbon in the recirculated solids in the lower part of the mixing zone252 before recirculated solids contact the entering gasifier feed vialine 241. Startup can be initiated by bringing the mixing zone 252 to atemperature from about 500° C. to about 650° C. and optionally byfeeding coke breeze or other solid, liquid, or gaseous fluid to themixing zone 252 to further increase the temperature of the mixing zone252 to about 900° C.

A startup burner 215 can be used to start the gasifier 250 via line 216.Fuel for the startup burner 215 can be supplied via a startup fuel linevia line 233. Oxidant or process air for the startup burner 215 can besupplied via line 214. The startup burner 215 can be a directpropane-fired burner operated to heat the gasifier 250 to a temperaturefrom about 500° C. to about 650° C. Liquid fuels, such as diesel, canalso be used, based on their availability. The startup burner 215 can bestarted at a system pressure of ranging from about 500 kPa to about 550kPa, and can operate at pressures ranging from about 950 kPa to about1,050 kPa.

Temperature variations in the gasifier 250 can be dampened by largeamounts of solids circulating in the gasifier 250. The circulatingsolids also can serve to rapidly heat the incoming gasifier feed vialine 241 which can minimize tar formation.

The mixing zone 252 can be operated at pressures of from about 100 kPato about 4500 kPa to increase thermal output per unit reactorcross-sectional area and enhance energy output in any subsequent powercycle. For example, the mixing zone 252 can be operated at pressures orfrom about 250 kPa to about 4000 kPa, from about 500 kPa to about 3000kPa, or from about 750 kPa to about 2500 kPa.

The raw syngas in line 251 produced in the gasifier 250 can be similarto the raw syngas in line 151 discussed and described above withreference to FIG. 1. Steam can be added with the oxidant stream via line214 to the mixing zone of the gasifier to moderate temperature rise at apoint of introduction of the oxidant. Steam can also be supplied to themixing zone of the gasifier 250 to control hydrogen to carbon monoxideratios (H₂:CO) within the gasifier 250. Since the outlet temperature ofthe gasifier 250 can be proportionately less than comparable gasifiers(e.g., slag type), the amount of thermal heat versus chemical heat inthe raw syngas via line 251 can be comparably less in the gasifier 250.Steam can be used to adjust by shift the H₂:CO ratio with a smallerenergy penalty than other entrained flow gasifiers operating at highertemperatures. Because of the reduced operating temperature within thegasifier 250 (i.e., less than 1,600° C.), less energy can be consumed tocontrol and optimize the H₂:CO ratio, thus the production of hydrogencan be increased without a commensurate increase in steam demand withinthe gasifier 250. The raw syngas via line 251 leaving the gasifier 250can have a H₂:CO of ranging from about 0.6:1 to about 1.3:1. Forexample, the H₂:CO ratio can be about 0.7:1 to about 1.2:1, about 0.8:1to about 1.1:1, or about 0.9:1 to about 1:1.

A gasifier bottoms drain pot 255 can be used to de-inventory ash fromthe gasifier 250 during turnarounds. Other accumulated ash in thestandpipe 259 can be withdrawn from a particulate transfer device, e.g.,a seal leg to maintain an ash level within the standpipe 259. Solidsfrom the gasifier bottoms drain pot 255 can be fed to storage and/or bedisposed of via line 256.

The raw syngas in line 251 can exit the gasifier at a temperature offrom about 575° C. to about 1,050° C. The raw syngas in line 251 can becooled using one or more coolers 270 (“primary coolers”) to provide acooled raw syngas stream 286 prior to entry into the particulate removalsystem 290.

The cooler 270 can include one or more heat exchangers or heatexchanging zones (three are shown 271, 280, and 285) arranged in series.The raw syngas in line 251 can be cooled by indirect heat exchange inthe first heat exchanger (“first zone”) 271 to a temperature of fromabout 260° C. to about 820° C. The cooled raw syngas exiting the firstheat exchanger 271 via line 272 can be further cooled by indirect heatexchange in the second heat exchanger (“second zone”) 280 to atemperature of from about 260° C. to about 705° C. The cooled raw syngasexiting the second heat exchanger 280 via line 282 can be further cooledby indirect heat exchange in the third heat exchanger (“third zone”) 285to a temperature of from about 260° C. to about 430° C.

The raw syngas in line 251 can be cooled using a heat transfer medium.The heat transfer medium can be saturated steam, boiler feed water, orthe like. The heat transfer medium via line 283 can be introduced to thesyngas cooler 270. Heat from the raw syngas can be indirectlytransferred to the heat transfer medium to provide superheated or highpressure superheated steam that can be recovered via line 281. Thesuperheated or high pressure superheated steam via line 281 can be usedto power one or more steam turbines (not shown) that can drive adirectly coupled electric generator (not shown), for example. Condensaterecovered from the steam turbines can be recycled as boiler feed waterto cool the syngas and produce steam.

The heat transfer medium via line 283 can be heated within the thirdheat exchanger (“economizer”) 285 to provide the cooled syngas via line286 and a boiler feed water via line 287. The boiler feed water via line287 can be saturated or substantially saturated at the processconditions. The boiler feed water via line 287 can be introduced(“flashed”) to one or more steam drums or separators 275 to provide aheated water via line 277 to feed into the steam generator 271.

The superheated or high pressure superheated steam via line 281 from thesyngas cooler 270 can have a temperature of about 400° C. or more, 425°C. or more, 450° C. or more, 475° C. or more, 500° C. or more, or 550°C. or more. The superheated or high pressure superheated steam via line281 can have a pressure of about 4,000 kPa or more, about 4,500 kPa ormore, about 5,000 kPa or more, about 5,550 kPa or more, about 6,000 kPaor more, about 6,500 kPa or more, about 7,000 kPa or more, or about7,500 kPa or more.

Boiler feed water via line 277 from the separator 275 can be introducedto the first heat exchanger (“steam generator”) 271 and heated againstraw syngas in line 251 thereby producing steam which can be introducedto the separator 275 via line 273. The steam returned to the separator275 via line 273 can exit via line 276 for superheating in the secondheat exchanger 280 to provide superheated or high pressure superheatedsteam via line 281 for use in the one or more steam turbines (notshown). Solids buildup in the separator 275 can be controlled by blowingdown a small amount of water via line 278.

Any one or all of the heat exchangers 271, 280, 285 (three are shown)can be shell-and-tube type heat exchangers. The raw syngas in line 251can be supplied in series to the shell-side or tube-side of the firstheat exchanger 271, second heat exchanger 280, and third heat exchanger285. The heat transfer medium can pass through either the shell-side ortube-side, depending on which side the raw syngas is introduced. In oneor more embodiments, the raw syngas in line 251 can be supplied inparallel (not shown) to shell-side or tube-side of the first heatexchanger 271, second heat exchanger 280, and third heat exchanger 285and the heat transfer medium can pass serially through either theshell-side or tube-side, depending on which side the raw syngas isintroduced. Make-up heat transfer medium can be added via line 283.

The cooled syngas via line 286 can be introduced to the particulateremoval system 290 to partially or completely remove particulates fromthe cooled syngas to provide a separated, “particulate-lean,” or “clean”syngas via line 291, separated particulates via line 292, and condensatevia line 293. During startup, steam via line 288 can be supplied to theparticulate removal system 290 to preheat it. Although not shown, theone or more particulate removal systems 290 can optionally be used topartially or completely remove particulates from the raw syngas in line251 before cooling. For example, the raw syngas in line 251 can beintroduced directly to the particulate removal system 290, resulting inhot gas particulate removal (e.g., from about 550° C. to about 1,050°C.). Although not shown, two particulate removal systems 290 can beused. For example, one particulate removal system 290 can be upstream ofthe cooler 270 and one particulate removal system 290 can be downstreamof the cooler 270.

The one or more particulate removal systems 290 can include one or moreseparation devices such as conventional disengagers and/or cyclones (notshown). Particulate control devices (“PCD”) capable of providing anoutlet particulate concentration below the detectable limit of about 0.1ppmw can also be used. Illustrative PCDs can include, but are notlimited to, sintered metal filters, metal filter candles, and/or ceramicfilter candles (for example, iron aluminide filter material). A smallamount of high-pressure recycled syngas via line 289 can be used topulse-clean filters as they accumulate particles from the unfilteredsyngas.

One or more analyzers (two are shown 260, 265) can be placed downstreamof the gasifier 250 to detect the amount of sulfur or sulfurconcentration coming out of the gasifier 250. The analyzers 260, 265 cancommunicate with the first feeder 220 and/or the first lock hopper 110via communication links 261, 266, and/or 267 to facilitate control ofand/or maintenance of the sulfur concentration in the gasifier 250and/or in the raw syngas stream 251. The communication links 261, 266,and/or 267 can be wired, wireless, or a combination thereof.

The sulfur concentration can be measured by the analyzers 260, 265downstream of the gasifier 250 at a point where the temperature is coolenough to be sent to a tempering system (not shown) but upstream of anytreatment systems that would change the sulfur concentration of thesyngas, such as caustic wash step. For example, the first analyzer 260can measure the sulfur concentration in the cooled syngas via line 286after it has been cooled by the cooler 270. In another example, thesecond analyzer 265 can measure the sulfur concentration in theseparated syngas via line 291 after it has passed through theparticulate removal system 290. In yet another example, the firstanalyzer 260 can measure the sulfur concentration in the cooled syngasvia line 286 and the second analyzer 265 can measure the sulfurconcentration in the separated syngas via line 291. The analyzers 260,265 can be, but are not limited to, gas chromatographs, aerographs, gasseparators, or any combination thereof. The analyzers 260, 265 can bethe same or similar to the analyzer 160 discussed and described abovewith reference to FIG. 1.

Once the analyzers 260, 265 measure or determine the sulfurconcentration in the cooled syngas via line 286 and/or the separatedsyngas via line 291, the analyzers 260, 265 can output a signal and/ordata via the communication links 261, 266, and/or 267 to an operator(not shown), the first feeder 220, and/or the first lock hopper 110. Forexample, the first analyzer 260 can communicate via communication links261 and 267 to the first feeder 220 and/or the first lock hopper 110. Inanother example, the second analyzer 265 can communicate viacommunication links 266 and 267 to the first feeder 220 and/or the firstlock hopper 110. In yet another example, the analyzers 260, 265 can bothcommunicate information to the feeder via the communication links 261,266, and/or 267. Although not shown, communication and actuation of thefirst feeder 220 and/or the first lock hopper 110 can be facilitated byan operator and/or a control unit that can be local or remote to thesystem 200.

In operation, the first feeder 220 can be adjusted according to thesignal and/or data conveyed in the communication link 267. When thefirst analyzer 260 and/or second analyzer 265 detect an insufficientamount of sulfur in the cooled syngas via line 286 and/or the separatedsyngas via line 291, i.e., the sulfur concentration is lower thandesired, the first feeder 220 can be adjusted to increase the rate atwhich the sulfur via line 222 is dispensed or conveyed to the gasifierfeed system 240 and/or the rate at which the sulfur via line 223 isdispensed to the storage bin 242 of the gasifier feed system 240. Aninsufficient amount of sulfur in the cooled syngas via line 286 can bedefined as a sulfur concentration of less than about 0.05 vol %, about0.1 vol %, or about 0.2 vol %, based on the total volume of the cooledsyngas in line 286. An insufficient amount of sulfur in the separatedsyngas via line 291 can be defined as a sulfur concentration of lessthan about 0.05 vol %, about 0.1 vol %, or about 0.2 vol %, based on thetotal volume of the separated syngas in line 291.

When the analyzers 260, 265 detect an excess amount of sulfur in thecooled syngas via line 286 and/or the separated syngas via line 291,i.e., the sulfur concentration is too high, the first feeder 220 can beadjusted to decrease the rate at which the sulfur via line 222 isdispensed or conveyed to the lock hopper 130 and/or the rate at whichthe sulfur via line 223 is dispensed to the storage bin 242 of thegasifier feed system 240. For example, when the sulfur concentration inthe cooled syngas via line 286 increase above about 0.3 vol %, about 0.4vol %, or about 0.5 vol %, about 0.6 vol %, about 0.7 vol %, about 0.8vol %, about 0.9 vol %, or about 1 vol %, the amount of sulfur dispensedto the locker hopper 130 and/or the gasifier feed system 240 can bereduced or stopped. In another example, when the sulfur concentration inthe separated syngas via line 291 increases above about 0.3 vol %, about0.4 vol %, or about 0.5 vol %, about 0.6 vol %, about 0.7 vol %, about0.8 vol %, about 0.9 vol %, or about 1 vol %, the amount of sulfurdispensed to the locker hopper 130 and/or the gasifier feed system 240can be reduced or stopped.

All adjustments to the first feeder 220 based on the sulfurconcentration(s) detected by the analyzers 260, 265 can be automaticadjustments. In another example, the adjustments can be actuated by acontroller (not shown) that receives one or more signals and/or datafrom the analyzers 260, 265 via the communication links 261, 266, 267 orother communication links (not shown). The amount of sulfur dispensed bythe first feeder 220 can also be adjusted manually based on the signalsand/or data sent by the analyzers 260, 265.

Embodiments of the present disclosure further relate to any one or moreof the following paragraphs:

1. A method for maintaining a sulfur concentration in a syngas,comprising combining sulfur and a carbonaceous material to produce asulfur containing carbonaceous feed; gasifying at least a portion of thesulfur concentration in the syngas; and adjusting an amount of sulfuradded to the carbonaceous material based on the detected sulfurconcentration.

2. The method of paragraph 1, wherein the carbonaceous materialcomprises coal, coke, petroleum, biomass, or any combination thereof.

3. The method of paragraph 1 or 2, wherein the syngas has a desiredsulfur concentration of at least 0.1 vol %.

4. The method according to any one of paragraphs 1 to 3, wherein thecarbonaceous material has an average particle size of about 50 micronsto about 500 microns.

5. The method of paragraph 4, wherein the added sulfur has an averageparticle size of from about 50 microns to about 500 microns.

6. The method according to any one of paragraphs 1 to 5, wherein thesulfur is detected using gas chromatography, spectrometry, vapor-phasechromatography, gas-liquid partition chromatography, or a combinationthereof.

7. The method of paragraph 6, wherein the sulfur containing carbonaceousmixture has an average particle size of about 400 microns or less.

8. The method according to any one of paragraphs 1 to 7, wherein thesulfur containing carbonaceous feed is gasified in a transport gasifier.

9. The method according to any one of paragraphs 1 to 7, wherein thesulfur containing carbonaceous feed is gasified in a fluidized bedgasifier.

10. The method according to any one of paragraphs 1 to 7, wherein thesulfur containing carbonaceous feed is gasified in an entrained flowgasifier.

11. The method according to any one of paragraphs 1 to 7, wherein thesulfur containing carbonaceous feed is gasified in a fixed bed gasifier.

12. A method for maintaining sulfur concentration in syngas, comprisingadding sulfur to a carbonaceous material to produce a sulfur containingcarbonaceous containing at least 0.05 vol % sulfur; introducing thesulfur containing carbonaceous feed to a transport gasifier to produce asyngas; detecting a sulfur concentration in the syngas; and adjusting anamount of sulfur added to the carbonaceous material based on thedetected sulfur concentration to maintain the sulfur concentration inthe syngas at about 0.1 vol % or more.

13. The method of paragraph 12, further comprising increasing the amountof sulfur added to the carbonaceous material when the sulfurconcentration in the syngas is below 0.1 vol %.

14. The method of paragraph 12 or 13, further comprising decreasing theamount of sulfur added to the carbonaceous material when the sulfurconcentration in the syngas is above about 0.4 vol %.

15. A method for maintaining sulfur concentration in syngas, comprisingadding sulfur at a controlled rate to a carbonaceous material to producea sulfur containing carbonaceous mixture, wherein a first feeder adjuststhe controlled rate of the sulfur; introducing the sulfur containingcarbonaceous mixture to a feed system to produce a sulfur containingcarbonaceous feed; introducing the sulfur containing carbonaceous feedto a gasifier operated at conditions sufficient to produce a syngashaving a sulfur concentration of about 0.1 vol % to about 0.4 vol %;detecting a sulfur concentration in the syngas; adjusting the firstfeeder to increase the rate sulfur is added to the carbonaceous materialwhen the sulfur concentration is below 0.1 vol %; and adjusting thefirst feeder to decrease the rate sulfur is added to the carbonaceousmaterial when the sulfur concentration is above 0.4 vol %.

16. The method of paragraph 15, further comprising changing the pressureof the sulfur containing carbonaceous material from atmospheric pressureto a gasifer operating pressure.

17. The method of paragraph 15 or 16, wherein the gasifier operates attemperatures ranging from about 700 C to 1,000 C.

18. The method according to any one of paragraphs 15 to 17, furthercomprising introducing the syngas to one or more coolers to produce acooled syngas, wherein the sulfur concentration of the syngas isdetected after the syngas has been cooled.

19. The method of claim 18, further comprising introducing the cooledsyngas to a particulate control device to partially or completely removeparticulates from the cooled syngas to produce a particulate-lean syngasand separated particulates; detecting a sulfur concentration in theparticulate-lean syngas with a second analyzer; adjusting the meteredfeeder to increase the rate sulfur is added to the carbonaceous materialwhen the sulfur concentration of the particulate-lean syngas is belowthe first threshold; and adjusting the metered feeder to decrease therate sulfur is added to the carbonaceous material when the sulfurconcentration of the particulate-lean syngas the above a secondthreshold.

20. The method according to any one of paragraphs 15 to 19, wherein thegasifier operates at a pressure ranging from about 750 kPa to about2,500 kPa.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges from any lower limit to any upper limit arecontemplated unless otherwise indicated. Certain lower limits, upperlimits, and ranges appear in one or more claims below. All numericalvalues are “about” or “approximately” the indicated value, and take intoaccount experimental error and variations that would be expected by aperson having ordinary skill in the art.

Various terms have been defined above. To the extent a term used in aclaim is not defined above, it should be given the broadest definitionpersons in the pertinent art have given that term as reflected in atleast one printed publication or issued patent. Furthermore, allpatents, test procedures, and other documents cited in this applicationare fully incorporated by reference to the extent such disclosure is notinconsistent with this application and for all jurisdictions in whichsuch incorporation is permitted.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

1. A method for maintaining a sulfur concentration in a syngas,comprising: combining sulfur and a carbonaceous material to produce asulfur containing carbonaceous feed; gasifying at least a portion of thesulfur containing carbonaceous feed to produce a syngas; detecting asulfur concentration in the syngas; and adjusting an amount of thesulfur combined with the carbonaceous material based on the detectedsulfur concentration.
 2. The method of claim 1, wherein the carbonaceousmaterial comprises coal, coke, petroleum, biomass, or any combinationthereof.
 3. The method of claim 1, wherein the syngas has a sulfurconcentration of at least 0.1 vol %.
 4. The method of claim 1, whereinthe carbonaceous material has an average particle size of about 50microns to about 500 microns.
 5. The method of claim 4, wherein thesulfur has an average particle size of from about 50 microns to about500 microns.
 6. The method of claim 1, wherein the sulfur is detectedusing gas chromatography, spectrometry, vapor-phase chromatography,gas-liquid partition chromatography, or any combination thereof.
 7. Themethod of claim 6, wherein the sulfur containing carbonaceous mixturehas an average particle size of about 400 microns or less.
 8. The methodof claim 1, wherein the sulfur containing carbonaceous feed is gasifiedin a transport gasifier.
 9. The method of claim 1, wherein sulfurcontaining carbonaceous feed is gasified in a fluidized bed gasifier.10. The method of claim 1, wherein the sulfur containing carbonaceousfeed is gasified in an entrained flow gasifier.
 11. The method of claim1, wherein the sulfur containing carbonaceous feed is gasified in afixed bed gasifier.
 12. A method for maintaining sulfur concentration insyngas, comprising: adding sulfur to a carbonaceous material to producea sulfur containing carbonaceous feed containing at least 0.05 vol %sulfur; introducing the sulfur containing carbonaceous feed to atransport gasifier to produce a syngas; detecting a sulfur concentrationin the syngas; and adjusting an amount of sulfur added to thecarbonaceous material based on the detected sulfur concentration tomaintain the sulfur concentration in the syngas at about 0.1 vol % ormore.
 13. The method of claim 12, further comprising increasing theamount of sulfur added to the carbonaceous material when the sulfurconcentration in the syngas is below 0.1 vol %.
 14. The method of claim12, further comprising decreasing the amount of sulfur added to thecarbonaceous material when the sulfur concentration in the syngas isabove about 0.4 vol %.
 15. A method for maintaining sulfur concentrationin syngas, comprising: adding sulfur at a controlled rate to acarbonaceous material to produce a sulfur containing carbonaceousmixture, wherein a first feeder adjusts the controlled rate of thesulfur; introducing the sulfur containing carbonaceous mixture to a feedsystem to produce a sulfur containing carbonaceous feed; introducing thesulfur containing carbonaceous feed to a gasifier operated at conditionssufficient to produce a syngas; detecting a sulfur concentration in thesyngas; adjusting the first feeder to increase the rate sulfur is addedto the carbonaceous material when the sulfur concentration is below 0.1vol %; and adjusting the first feeder to decrease the rate sulfur isadded to the carbonaceous material when the sulfur concentration isabove 0.4 vol %.
 16. The method of claim 15, further comprising changingthe pressure of the sulfur containing carbonaceous material fromatmospheric pressure to a gasifer operating pressure.
 17. The method ofclaim 15, wherein the gasifier operates at temperatures ranging fromabout 700 C to 1,000 C.
 18. The method of claim 15, further comprisingintroducing the syngas to one or more coolers to produce a cooledsyngas, wherein the sulfur concentration in the syngas is detected afterthe syngas has been cooled.
 19. The method of claim 18, furthercomprising: introducing the cooled syngas to a particulate controldevice to partially or completely remove particulates from the cooledsyngas to produce a particulate-lean syngas and separated particulates;detecting a sulfur concentration in the particulate-lean syngas with asecond analyzer; adjusting the metered feeder to increase the ratesulfur is added to the carbonaceous material when the sulfurconcentration of the particulate-lean syngas is below a first threshold;and adjusting the metered feeder to decrease the rate sulfur is added tothe carbonaceous material when the sulfur concentration of theparticulate-lean syngas the above a second threshold.
 20. The method ofclaim 15, wherein the gasifier operates at a pressure ranging from about750 kPa to about 2,500 kPa.